How to interpret the hurricane track cone

It’s difficult to fathom a hurricane threat without the aid of the National Hurricane Center’s five-day forecast track cone.

But the most popular graphic disseminated by the National Hurricane Center, the Cone Of Uncertainty, didn’t exist before 2003 and the public relied on simple three-day general storm location graphics that were in use since 1964.

Refinements in the forecast over the years have resulted in today’s two-day forecast being as accurate as a one-day forecast was a decade ago and a five-day forecast now is more accurate than a three-day forecast was two decades ago.

Based on these advances, the National Hurricane Center recalculates the width of the cone most years to a narrower size.

Accuracy in hurricane track forecasting is measured by “track error” — the distance between the predicted position of a storm’s center and its later, actual position.

Storms stay in the cone on average 67% of the time and the size of the cone fluctuates based on past forecast misses and successes.

Those forecast error over the past 5 years predicates this year’s cone width which does not change much for the Atlantic basin this season compared to 2022.

The cone starts out narrow for the short term forecasts 12 or 24 hours out and grows bigger as it approaches the five-day estimate because long range predictions are typically less accurate.

Understand that a storm can be a threat even if your location is on the cone’s outskirts. Remember the track cone is an approximate location reached over a set time period. It doesn’t show you flooding rains, storm surge, or tornadoes predictions.

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